Floor board anti squeak welding

[farmputzer]

When installing the anti squeak welting on the floor boards, what was done at the underneath corners? Was a 90 degree notch made so that there was only one thickness? What was done with the underneath welting in the center of the top board where the board is recessed for the bell housing? How far apart were the tacks? Did the welting have some sort of preservative on it?
Thanks,
Farmputzer